Time-Triggered Protocol (TTP),or time-triggered bus,is a bus used in safety-critical,real-time control system adopting the time-triggered communication mechanism based on global time.Considering the requirements of clock synchronization on high precision and fault tolerance,we studied the algorithm of clock synchronization of TTP,established a TTP node model and the algorithm of clock synchronization by using OMNeT++.Simulation was made to the algorithm of clock synchronization and verified the correctness of it.With enough synchronization period,the precision can be less than 1 μs.